Mu’ath Adlouni

Introduction. Peri-procedural stroke is a common complication of carotid stent placement with an incidence ranging from 4%-7.2% depending on the age of the patient^1,2. The process of stent placement gives rise to peri-procedural stroke risk via various mechanisms such as stent thrombosis, vasospasm, hemodynamic instability, and restenosis^3,4. This has led to numerous stent designs, each attempting to mitigate one of the aforementioned factors but with the common goal of increasing biocompatibility. Additionally, a popular target to achieve this increase being the promotion of vessel reendothelialization. Materials. New stent designs that were analyzed for the purpose of reducing peri-procedural stroke risk include Slit modified covered stent membranes made of polytetrafluoroethylene (PTFE)⁵, Micropatterned Thin Films (MTF) that shroud self-expanding stent in a micromesh network⁶, Drug-eluting stents with the variable release of VEGF DNA plasmid and paclitaxel⁷, and Biodegradable stents made of Zinc, Magnesium, and Copper alloy with a slow release of Zinc, excellent mechanical properties, and rapidly accelerated degeneration⁸. Results. Covered stents enhance biocompatibility by reducing fragmentation of atherosclerotic plaques while maintaining blood flow⁵. MTF stents increase plaque coverage and endothelial cell proliferation by capturing circulating progenitor endothelial cells in the blood within its complex geometry⁶. Drug eluding stents make use biodegradable polymers to promote endothelial cell growth using an initial dosing of VEGF and inhibiting restenosis from vascular smooth muscle cells via delayed release of paclitaxel⁷. Lastly, Biodegradable Zinc alloy stents slowly deliver small doses of Zn+2, a known enhancer of endothelial cell growth and inhibitor of smooth muscle proliferation thereby increasing its biocompatibility⁸. Discussion. There are many efforts towards increasing the biocompatibility of stents. While many various stent designs take unique approaches through materials, mechanics, and drugs show promise; there remains no standardized method to evaluate the underlying properties of stents and their cause of periprocedural stroke in a clinical setting. To begin appropriately designing stents that are targeted toward reducing periprocedural stroke, essential research that defines those parameters needs to be completed.

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